Regensburg 2010 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 64: Quantum Dots and Wires: Optical Properties VI

HL 64.3: Talk

Friday, March 26, 2010, 10:45–11:00, H14

Strain tuneable photoluminescence from natural InAs quantum dots — •Matthias Klingbeil, Matthias Grave, Sven Wildfang, Wolfgang Hansen, Detlef Heitmann, and Stefan Mendach — Institut für Angewandte Physik,Jungiusstr 11, 20355 Hamburg

The growth of self-assembled InAs-quantum dots on a GaAs substrate is inherently connected to the formation of an InAs wetting layer. Recently it was shown that fluctuations in the composition and thickness of this wetting layer lead to the formation of shallow zero dimensional confinements [1], so called natural InAs quantum dots [nQD]. The photoluminescence of these nQD is typically located in the low energy tail of the wetting layer emission. Here, we show that the nQD emission can be shifted away from the wetting layer and increased in intensity by the application of stress. For this purpose we embed the nQD in free standing lamellae that can be bent by a glass needle during the photoluminescence experiment. In the unstrained state all nQDs exhibit a low intensity. The application of strain amplifies the luminescence of certain nQDs and red shifts their emission away from the wetting layer signal by up to 40 meV.

[1] Babinski et al., Appl. Phys. Lett. 92, 171104 (2008).